| 1 | D & T Company | Denver, CO 80210 | Oil & Gas Operator | Jun 1983 |
| 2 | Dale Operating Company | Dallas, TX 75201 | Oil & Gas Operator | Dec 2024 |
| 3 | Dalen Resources Oil & Gas Co. | Dallas, TX 75206 | Oil & Gas Operator | Jun 2010 |
| 4 | Dallas Petroleum Group, LLC | Dallas, TX 75379 | Oil & Gas Operator | Dec 2024 |
| 5 | Dallas Production, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Mar 2021 |
| 6 | Dan A. Hughes Company, L.P. | Beeville, TX 78104 | Oil & Gas Operator | Jul 2024 |
| 7 | Dantex Oil & Gas, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Aug 2003 |
| 8 | Davis Bros. Oil Producers, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | Apr 2020 |
| 9 | Davis Gulf Coast, Inc. | Tulsa, OK 74103 | Oil & Gas Operator | Dec 2024 |
| 10 | Deep Rock Resources, Inc. | Dallas, TX 75206 | Oil & Gas Operator | Dec 2024 |
| 11 | Deguello Operating LLC | Kilgore, TX 75663 | Oil & Gas Operator | Dec 2024 |
| 12 | Dekalb Energy Company | Oklahoma City, OK 73134 | Oil & Gas Operator | Oct 1996 |
| 13 | Delta Exploration Company Inc | Denver, CO 80202 | Oil & Gas Operator | Dec 2024 |
| 14 | Denali Oil & Gas Management, LLC | Houston, TX 77060 | Oil & Gas Operator | Dec 2012 |
| 15 | Devon Energy Production Company LP | Oklahoma City, OK 73102 | Oil & Gas Operator | Dec 2024 |
| 16 | Devon Louisiana Corporation | Houston, TX 77002 | Oil & Gas Operator | Oct 2019 |
| 17 | Diasu Oil & Gas Co., Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2016 |
| 18 | DJ Exploration, Inc. | San Antonio, TX 78257 | Oil & Gas Operator | Dec 2024 |
| 19 | Dominion Exploration & Production Inc | Houston, TX 77060 | Oil & Gas Operator | Apr 2015 |
| 20 | Dominion Oklahoma Texas E&P, Inc | Richmond, VA 23219 | Oil & Gas Operator | Sep 2018 |
| 21 | Dorado Oil Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Dec 2014 |
| 22 | Double Play Oil & Gas, Inc | Portland, TX 78374 | Oil & Gas Operator | Dec 2024 |
| 23 | Dreyfus, Louis Natural Gas Corp | Oklahoma City, OK 73134 | Oil & Gas Operator | Nov 2001 |
| 24 | Drillmar Energy, Inc. | Houston, TX 77079 | Oil & Gas Operator | Nov 2014 |
| 25 | Drillmar Operating Company | Houston, TX 77019 | Oil & Gas Operator | Jun 2013 |
| 26 | Dynamic Production, Inc. | Fort Worth, TX 76106 | Oil & Gas Operator | Dec 2024 |